1. Field of the Invention
The present invention generally relates to a housing structure with accessory equipment for power circuit breakers with a molded housing. In particular, the present invention relates to a housing structure intended to hold auxiliary control switches as supplementary devices, however, the housing in accordance with the present invention can also be used for other accessory equipment of a power circuit breaker.
2. Background Information
Such a housing structure is disclosed in U.S. Pat. No. 4,622,444, on which housing the upper part of the main housing, on one side or on both sides of the actuator handle, has a recess or recesses which are open on the side. An accessory device with an appropriately shaped accessory housing can be inserted into each of the recesses from the front, whereby the front walls of the main housing and of the accessory housing end at one another. For the correct insertion of the accessory equipment, on the two side walls of the accessory housing covered by the main housing, there are a pair of guide strips which are guided in a pair of guide grooves on the inside walls of the recesses of the upper part of the main housing. The accessory housing, on the outside wall, has a pair of retaining shackles pointing backward, for which there is an additional pair of guide grooves on the outside of the bottom part of the main housing. The additional pair of guide grooves have a locking lug, each for interaction with the respective elastic retaining shackles. Extending from the accessory housing, which is open on the back, an actuator element of the accessory device extends through an actuator opening in the bottom of the top part of the main housing into the inside of the power circuit breaker. The connection openings of the accessory device are on the uncovered outside wall of the accessory device.
The disadvantages of this known device include the fact that, for each accessory device, a corresponding recess is required and thus a maximum of two accessory devices can be inserted, that a special accessory housing is necessary for the accessory equipment, and that a number of means, all of which require close tolerances, are necessary for the guidance and mounting of the accessory housing. Thus, the insertion and the extraction of the accessory device typically requires a corresponding amount of skill and force, and the connections of the accessory equipment are not easy to install, since they are accessible only from the side.
German Utility Model No. 92 03 533, which corresponds to U.S. Pat. No. 5,362,933, discloses a power circuit breaker which has two recesses, one on either side of the actuator handle, located in the upper portion of the main housing, and which recesses can be covered by a pivoting cover. Accessory devices are located in the recesses, whereby these accessory devices are attached to the bottoms of the recesses and the electrical connection elements are oriented toward the front side. This publication does not disclose any information concerning the probable mechanical couplings between the power circuit breaker and the auxiliary control switches or accessory devices in the recesses.
German Laid Open Patent Application No. 42 35 504 discloses a housing structure for a power circuit breaker in which accessory devices enclosed by accessory housings are not attached directly in the upper portion of the main housing. In particular, an electrically insulating base is used, in which one or more accessory housings can be removably attached. The base itself is removably located in a recess. Since the base is located between the upper part and the accessory housings, the latter are not restricted by the shape and size of the recesses, and accessory devices with different accessory housings can be attached by using different bases. This publication also discloses a direct installation of the accessory housings in a recess in the top part. The retaining means used are elastic hooks which are molded onto the narrow sides of the accessory devices, which hooks enter into a locking connection with the upper part during the insertion of the accessory device, as well as a pivoting cover. The underside of the pivoting cover matches the shape of the accessory housings. The retaining means in this case function exclusively as retainers. The side walls of the recess act to some extent as guide means.